Crown assembly

ABSTRACT

A crown assembly for use on wrist watches having a crown provided with an axial blind bore. A stem has an end portion received in the blind bore and is fixedly coupled thereto by coupling means having an interference fit with the blind bore. The arrangement permits the crown assembly to be manufactured with the crown and stem made independently and of different materials.

United States Patent [1 1 3,866,409

Tanaka Feb. 18, 1975 [5 CROWN ASSEMBLY 3,595,008 7/1971 Piquerez i v 58/90 B Inventor: Kumiko m a, u b hi Japan $777,474 l2/l973 Plquerez 58/90 B [73] Assignec: t lfaisha Daini seikosha Primary E.\'aminerGe0rge H. Miller, Jr.

0 Attorney, Agent. or FirmR0bert E. Burns; [22] Filed: Dec. 27, 1973 Emmanuel J. Lobzito; Bruce L. Adams [21] Appl No: 428,872

[57] ABSTRACT [30] Foreign Application Priority Data D 19 1977 Jn In 47477 A crown assembly for use on wrist watches having 11 crown provided with an axial blind bore. A stem has an end portion received in the blind bore and is fixedly Coupled thereto y p g means having an [58] 58/90 B interference fit with the blind bore. The arrangement le 0 can permits the crown assembly to be manufactured with [56] References Cited the crown and stem made independently and of differ ent materials. UNITED STATES PATENTS 1062,63? 12/1936 Bulovu 58/90 B 5 Claims, 10 Drawing Figures 1 CROWN ASSEMBLY BACKGROUND OF THE INVENTION The present invention relates generally to wrist watches and more particularly to a crown assembly.

In conventional watches the crown generally has a stem or axis integral therewith. Thus if the crown is made of a soft material such as silver or some other material which cannot stand excessive stresses imposed on the stem when the crown is rotated or withdrawn it will cause failure of the stem.

If a precious metal is used for the crown the integral stern and crown becomes relatively expensive. Moreover, the integral construction raises production costs since it is harder to make than if the crown and stem were made independently.

SUMMARY OF THE INVENTION It is a principal object of the present invention to provide a crown assembly in which a crown and stem are made independently and coupled by coupling means.

The crown assembly according to the invention is used on wrist watches and comprises a crown and a stern made independently of each other. The stem has an end portion coupled to the crown which has a blind bore for receiving the end portion of the stem coupling means are provided on the end portion of the stern coupling it to the inner surfaces of the blind bore thereby to couple the crown and stem in a fixed assembly.

The coupling may be accomplished by providing coupling means that have an interference fit in the blind bore. This is accomplished by having a bushing circumferentially of the end portion of the stem received in the blind bore. The bushing is made of a resilient or deformable material that is deformed and presses against the stem end portion and the inner surfaces of the blind bore when forced into the blind bore with an interference fit.

The coupling means may be provided independently of the stem portion and the crown or the stem itself may have a bushing formed thereon integrally and made of a material that will provide an interference fit.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the crown assembly according to the invention will appear from the following description of an example of the invention, and the novel features will be particularly pointed out in the appended claims and drawings in which:

FIGS. 1 to 2c are prior art crown assemblies;

FIGS. 3A-3C are section views of crown assemblies according to the invention;

FIG. 4A is a section view of another embodiment of a crown assembly according to the invention;

FIG. 4B is a plan view of a component of the crown assembly in FIG. 4A; and

FIG. 5 is a cross section view ofa crown assembly according to the invention in which coupling means are provided integral with the stem.

DESCRIPTION OF THE PREFERRED EMBODIMENT A conventional crown is illustrated in'FIG. 1. The crown comprises a head portion a and a stem b. The head portion and stem are made integral of any desired metal. for example a precious metal.

As illustrated in the drawings in .FIGS. 2A-2B a crown assembly 1 is illustrated as having a blind bore 2. A stem 3 has an end portion extending axially into the blind bore 2 and is provided with a flange or collar 3a in FIG. 2A spaced axially from the very end of the stem. A bushing'4 made of a resilient or deformable material is disposed circumferentially of the end of the stem and has a diameter greater than that of the blind bore. The bore opening flares outwardly for allowing insertion of the stem and bushing thereon so that an interference may be established between the bushing 4 and the blind bore. In the embodiment in FIG. 2B the collar 3a is at the very end of the stem 3 and seats against a bottom 20 of the blind bore. The coupling means constituting the bushing 4 in conjunction with the collar 3a in this second embodiment carries out the coupling function.

The use of a collar on the stem may be avoided by constructing the stem with a minor diameter end portion 3b as illustrated in FIG. 2C and placing a coupling means constituting a deformable bushing 4 circumferentially of the reduced diameter 3b and having an interference and compressive fit as before described.

According to the invention another type of construction is employed with respect to the coupling means in which the bushing is provided with a lip circumferen tially thereof for engaging a recess circumferentially of the blind bore. This type of construction is illustrated in FIGS. 3A-3C. As seen in the drawings a crown assembly 1 has a blind bore 2 having a peripheral recess 2b undercut into the crown, which recess accordingly extends into the crown outwardly from the bore, between the inner and outer ends of the bore. A stem 3 is coupled to the crown by a bushing 4 having a periph eral lip a flaring outwardly from the body of the bushing and extending into the recess. In the constructions illustrated in FIGS. 3A-3C a collar 3a on the stem is provided at the end of the stem. The coupling means constituting a bushing 4 is seated there against and the lip a extends outwardly and generally in an axial direction of the stem 3 away from the end of the stem as shown and in each instance is seated against a surface of the peripheral recess 2b tending to maintain the coupling means 4 seated against the collar 3a of the corresponding stem. This also tends to avoid axial separation of the stem from the crown.

In the embodiment illustrated in FIG. 3C a stem 3 is provided with a constriction 3c and a lip a of a coupling means 4 is a split lip in cross section having an inner lip part thereof extending into the constriction 30. Any tendency of axial separation of the crown and stem is avoided since the inner lip will seat against the beveled part of the constriction 3c and the outer lip will seat against a corresponding surface of the peripheral recess 2b so that the fixed assembly is maintained.

A different construction is illustrated in FIGS. 4A-4B. In this illustration a crown assembly 1 has a crown assembled with a stem 3. The stem is provided with an end collar as shown and the crown has a peripheral recess 2b. A split ring 5 is inserted circumferentially of the stem and expanded into the peripheral recess and abuts against the end flange of the stem as illustrated.

Thus a coupling axially and in a circumferential direction is maintained by the resilient ring 5 and the stem.

While independent coupling means have been described in the embodiments heretofore disclosed, the flexible coupling may be provided integral with the stem as illustrated in FIG. 5. In this instance the stem 3 is made of a suitable plastic and an end collar 3a made integral therewith will constitute the coupling means. The collar has a lip configured similarly as heretofore described and received in a peripheral recess 2b of the crown. The end of the lip flares outwardly and abuts against a corresponding surface of the recess to maintain axial assembly of the crown and stem as before described. The end portion of the stem has an interference fit in the blind bore of the crown as before described.

The crown of the various embodiments can be made out of silver nickel or any other desired metal. The independent coupling means are made of a resilient or deformable material which is elastic and will tend to compress against the blind bore inner surfaces and against the stern surfaces for effecting a coupling thereof when inserted into the blind bore. The stem can be made of an elastic or plastic material in the various embodiments illustrated. ln the embodiment in which the coupling means is integral therewith the stem and coupling means may be made of a suitable plastic.

Those skilled in the art will recognize that the various components of the assembly can be made or machined independently greatly reducing the cost and the construction of the coupling means andthe stem can be made of a cheaper material than that of the crown thereby reducing overall costs.

What I claim and desire to secure by Letters Patent l. A crown assembly for use in a watch, comprising a metallic crown which has a blind bore and a peripheral, undercut recess of the bore; a stem having an end portion in the bore; and annular lip means extending outwardly from said end portion into the recess for coupling the crown to the stem.

2. A crown assembly according to claim 1, wherein said lip means is integral with said end portion of the stem.

3. A crown assembly according to claim 1, wherein said recessextends from the bore into said crown between inner and outer ends of the bore.

4. A crown assembly according to claim 3, wherein said stem has a collar secured to an end portion thereof and outwardly extending therefrom in said bore, and said lip means comprises a ring surrounding said stern, engaging said collar, and extending into the recess.

5. A crown assembly according to claim 4, wherein said ring is a split ring. 

1. A crown assembly for use in a watch, comprising a metallic crown which has a blind bore and a peripheral, undercut recess of the bore; a stem having an end portion in the bore; and annular lip means extending outwardly from said end portion into the recess for coupling the crown to the stem.
 2. A crown assembly according to claim 1, wherein said lip means is integral with said end portion of the stem.
 3. A crown assembly according to claim 1, wherein said recess extends from the bore into said crown between inner and outer ends of the bore.
 4. A crown assembly according to claim 3, wherein said stem has a collar secured to an end portion thereof and outwardly extending therefrom in said bore, and said lip means comprises a ring surrounding said stem, engaging said collar, and extending into the recess.
 5. A crown assembly according to claim 4, wherein said ring is a split ring. 